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TRnorm

Fireproof bulkhead

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I want to follow the considerable body of advice on this forum and (make and) fit a bulkhead between the petrol tank and the cockpit.

Although my searches have found many posts on the subject i cannot find any that suggest a thickness for the aluminium.

My guess is that fabricating the bulkhead without professional tools would be near impossible in 2mm, difficult in 1.5mm and OK in 1.2mm.

 

Those with such a bulkhead - What thickness is yours?

 

Thanks in advance

Norman

Edited by TRnorm

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For a race car you want it to be as light/ thin as possible to allow you to escape the car before the fire reaches the cockpit.......

 

For a road car 18 gauge is perfect welded in :)

 

Tom

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Thanks Tom and Alan,

I can see that Steel welded-in is the best.

I can see that Ali is much weaker but I was thinking of pop riveting it in very frequent intervals to help it maintain the petrol seal to the rest of the car.

Is there anyone out there who's used Ali and what do you reckon?

 

Norman

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Guest

Mine is aluminium and not a flimsy lightweight piece of metal. I can not measure the thickness, because it's upholstered. I needed the hand of a professional with a bending machine to shape the angle at the top.

 

Menno

 

'Welded in...' When I understand this correctly, you're about to consider welding a bulkhead between the cockpit and the tank? Bad idea! You need a removable bulkhead because you have to take it away when you've to change the tank sender (don't ask!). Go for a pretty thick sheet of aluminium and ask a local sheet metal worker to fold / angle it. It only takes seconds to put it in the correct shape.

Edited by Menno van Rij 2

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Hi Norm,

I'm not sure what shape it needs to be (Menno refers to a 'bend at the top'). Anyway Ali alloy can be as strong as you want, but at a cost.

If the basic shape is flat with subtle curve for back of rear seat then 2024T3 would work well and is strong - not sure if available on ebay

 

Aluminium is too soft and a pain to work - harder the better for cutting/filing.

 

Pop rivets are rather naff if you are after strength but at least they are easily available and will not break the bank.

Have a look at the LAS site for aircraft fasteners that do a proper job. http://www.lasaero.com/

 

1.5mm (16SWG, almost) is light, strong and workable,

 

Roger

Edited by RogerH

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Thanks Menno,

I'm getting the picture - thin'ish steel (1.2mm) welded or thicker Ali well anchored to the body. Not surprising I guess but it's good to get a range of views.

My car is freshly restored with gleaming paintwork that I'm reluctant to weld, and I would prefer to maintain access to the tank area from both sides without grinding away welds.

At my age I don't expect to be leaning it on the door handles, and a decent attempt to improve this safety aspect is not unreasonable, i feel.

 

But as always it's really good to get the full picture in order to formulate ones own approach - thanks everyone.

Norman

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Thanks Roger - perhaps I should reserve final judgement until all the votes are counted!

 

I've not heard of 2024T3 before so will research that with interest. I guess the link to aircraft grade Spruce wasn't the link you intended, but useful for the Marcos boys!

 

Norman

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Hi Norman,

 

Very glad you are taking the risk of fire seriously and thinking how to do it. If you'd like a precut alloy panel of suitable thickness, motorsport specialists TR Enterprises/Racetorations/Revingtons and a load of the others can offer them and maybe a comprehensive fitting kit also. I understand the pricing will be about £60 ish range depending upon what you go for.

Fitting will be comprised of bedding it onto a non setting sealer Indasa windscreen sealer (or other non tumescence substance is good) and the riveting in place, has the advantage of non scorching any paintwork. Don't get hung up upon the fixing in place, the RAC is quite happy for race cars to have riveted and sealed rear fireproof bulkheads in place and race cars are likely to have much worse impacts than normal road use.

 

You don't say what car you are fitting it to but if a TR4a/5/6 beware of the inherent front wishbone fixing weakness with only one bolt on the rear item, do a search for the item if interested, also consider a Roll cage to preserve the space around the occupants and also add extra strength against side impact intrusion, not a lot of money and another life saver even in normal road use.

 

Mick Richards

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If its painted already I'd do the pop-rivets.

 

You will find there are two funny shaped, curvy areas right at the top of the wheel arches.

I did these with separate pieces.

 

You can still reach the tank-sender with the bulk-head in place.

You can't remove it from the tank, but I don't think you can do this even if you don't have a bulk-head.

 

Remember there must be a way to get wiring from the drivers-side into the boot. I used a cable gland.

 

You will see that I fixed "dead-sheet" on mine. This will resonate somewhat otherwise.

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For what it's worth I have installed a 3 mm thick fire retardant/resistant neoprene rubber which is stuck on the cardboard and on the inner boot panel. Easy to install, heavy but stinks like a septic tank for a couple of days. Electric pump is installed outside just above the trailing arm LH

 

Something like this: http://www.rubbersheetroll.com/neoprene-rubber-flame-retardant.html

Edited by Geko

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I want to follow the considerable body of advice on this forum and (make and) fit a bulkhead between the petrol tank and the cockpit.

Although my searches have found many posts on the subject i cannot find any that suggest a thickness for the aluminium.

My guess is that fabricating the bulkhead without professional tools would be near impossible in 2mm, difficult in 1.5mm and OK in 1.2mm.

 

Those with such a bulkhead - What thickness is yours?

 

Thanks in advance

Norman

Norm I fabricated one from 2mm aluminium in the TR6 - too thick and difficult to shape to fit. For the TR4 I bought one from Moss (I think) which I believe was 0.8mm. Much better

 

Graze

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The Revington firewall for a sidescreen is a flat thin aluminium sheet that is cut to an approximate shape. It requires considerable fettling to make it fit and as Menno says, you need to be able to remove it to access the fuel tank sender.

 

Rgds Ian

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The Revington firewall for a sidescreen is a flat thin aluminium sheet that is cut to an approximate shape. It requires considerable fettling to make it fit and as Menno says, you need to be able to remove it to access the fuel tank sender.

 

Rgds Ian

The Revington one for 4/5/6 isnt much better, Very approximate shape for the centre piece in 20SWG ally and two bits of 18swg steel for the outers that you have absolutely no chance of fitting unless you had the deck off.So I tend to make my own now as its easier and use I use18 or 20SWG ally

Stuart.

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Stuart, I found the Revington ally panel a 'reasonable' fit and with a bit of hammering and trimming got it in OK with my riveter. The mild steel 'ears' they supply for the remaining holes were impossible for me - I have used a flexible firewall product (Zircotech) for the time being before I return with my tin snips and some thin aluminium in the winter.

 

Snowy

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When you have a funny sheet-metal shape to make start with a cereal-packet and scissors.

 

Go at it as many times as it takes to get a perfect pattern.

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Thanks Alan - I will get the kids to eat more Shreddies ! Snowy

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I Must be missing something here!

On a side screen car you have tank clamps that attach below and behind the rear trim panel. How do you fit a fire blank and leave access to them?

 

If you have to remove it, kind of defeats the object of the exerise.

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Rodbr -

 

You leave a small cutout for the end of the tank strap.

This can be sealed but removed should the tank need

to be removed.

 

It's extremely difficult to completely seal the fireproof

bulkhead to fully protect against an extreme situation.

 

Bulkheads welded in will give a bit more strength to

the rear body, which can't be a bad thing!

 

AlanR

 

 

AlanR

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My 10 cents' worth....use the dog-kennel trim panel as your template, thin alloy sheet for that section & cardboard templates for the side fillet sections in the same alloy. Pop rivets every 4cm & Sikkaflex/DumDum etc to seal.

The bottom line here is about satisfying scrutineers; an accident big enough to rupture the fuel tank is unlikely to require a fireproof bulkhead, rather a coffin or two. The filler to tank hose is the weakest part & could be pulled away from the tank in a severe rear-ender by the rear deck; I have seen plenty of wrecked road & race TRs & it's yet to happen.

We are fortunate to drive cars that, by accident or design, actually behave remarkably well in heavy accidents as long as they stay "shiny side up" & the tank position, though seemingly dangerous, is in fact quite sensible.

Ask any MG driver that's had a big one up the back end (missus)

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SPmpWolf,

 

I think broadly you are correct Jon, but Norman isn't asking about competition use just about reducing the risk in his road going TR, and counter intuitively I regard the risks on the road being as bad ! On a race circuit you expect things may go wrong evaluate the risks and change your cars shortcomings to ameliorate them, the scrutineer is there to ensure you've made at least the minimum effort, unfortunately on road going cars the MOT is not a satisfactory substitute !

 

As you've said keeping the car the shiny side up is good for the occupants, and if this is a condition too far because you've been T boned by "white van man" and the worst happens inverting the car, well the roll cage behind the passengers keeps their heads from developing flats caused by the road, and the fireproof bulkhead helps prevent the compartment being flooded with 10 gallons of fuel because of fuel tank rupture or the pipe coming off the filler.

 

We can't make a 50 year old car totally safe but we can make it a whole lot better, and if anybody is wondering what will make you feel worse than awakening the day after being involved in an accident that writes off your TR, I'd venture it's awakening in a burns unit in agony with 30% burns and realising that your wife or partner suffered even worse burns and didn't make it. This isn't deliberately graphic, it's what happens if you decline to fit the correct safety equipment for whatever reason you use to justify it, if you don't fit this equipment then you take the gamble, and it's so easy and cheap to do.

 

 

Mick Richards

Edited by Motorsport Mickey

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Such a good idea, but forgive my ignorance - boot side or cockpit side of the existing brackets in front of the tank

 

Thanks

 

Keith

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Cockpit side Keith, it's a lot easier to fit...and I agree wholeheartedly with Micky.

 

Cheers

 

Tony

 

PS. My fireproof bulkhead is 2mm steel. I chose this because it strengthens the body and restricts flexiing...much like adding a Hardtop does.

 

Cheers

 

Tony

Edited by Tony Millward

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